1. Field of the Invention
This invention relates to an irrigation drive unit and more particularly to an irrigation drive unit having increased traction and flotation. More particularly the irrigation drive unit has increased traction and flotation due to providing an extra set of driven wheels thereon.
2. Description of the Related Art
Self-propelled irrigation systems or mechanized irrigation systems such as lateral move irrigation systems, center pivot irrigation systems, and corner irrigation systems normally utilize a plurality of spaced-apart drive units or towers which support an elongated irrigation pipeline which moves over the area to be irrigated. In the past, most prior art drive units comprise an elongated base beam which is disposed transversely to the longitudinal axis of the pipeline with a drive wheel at the opposite ends of the base beam. In some prior art designs, three or more drive wheels have been rigidly attached to the base beam. A tower structure extends upwardly from the base beam to the pipeline. The number of tires or wheels used on a drive unit relates directly to the weight distribution. The prior art systems do not allow the driven wheels to pivot over uneven terrain or when the drive wheels cross ridges which causes inconsistent weight distribution. Traction loss and rutting can appear if all the driven wheels are unable to contact the ground with approximately equal weight distribution.